title: Possible mechanism of growth inhibition by Scutellaria baicalensis in an estrogen-responsive mouse tumor cell line.
abstract: We have studied the effects of Saiboku-to, a traditional Chinese medicine having suppressive activities for leukotriene production and release, on the proliferation of the estrogen-responsive mouse Leydig tumor cell line B-1F. In our previous reports, it is shown that Saiboku-to promotes, but Scutellaria baicalensis, one of the components (herbs) of Saiboku-to, significantly inhibits the proliferation of B-1F cells in vitro and in vivo, and induces DNA fragmentation and morphological changes such as nuclear aggregation and fragmentation. In this study, we examined telomerase activity, cell cycle, polyunsaturated fatty acid metabolism and expression of nuclear factor κB (NF-κB) in order to determine the mechanism of growth inhibition in B-1F cells treated with Scutellaria baicalensis. Telomerase activity was decreased in a dose-dependent manner in treated B-1F cells. Cellular populations in the sub-G0/G1 and G2/M phases were increased, but those in M phase had no change. Although cyclin D1 mRNA was highly expressed in the presence of estradiol (E2), cyclin A and E mRNA levels did not significantly change. When B-1F cells were treated with Scutellaria baicalensis, expression of cyclin D1 was suppressed and that of p21 was inversely increased. Moreover, Scutellaria baicalensis influenced arachidonic and linoleic acid metabolism, and increased production of 13(S)-HODE. In the presence of E2 Scutellaria baicalensis decreased expression of NF-κB p65 to 0.71-fold in B-1F cells. These results show that Scutellaria baicalensis might induce cell cycle arrest at G1 phase and apoptosis via inhibition of telomerase activity, changes of enzymatic activities in polyunsaturated fatty acid metabolism and suppression of NF-κB.
authors.affiliation: Department of Pathology, Research Institute, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3 Nakamichi, Higashinari 537-8511, Japan.
authors.forename: Teruko
authors.initials: T
authors.lastname: Murashima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Katayama
authors.forename: Kimura
authors.initials: K
authors.lastname: Shojiro
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Nishizawa
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004967:Estrogens / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D008516:Medicine, Chinese Traditional; D051379:Mice; D016328:NF-kappa B / Q000235:genetics; D010936:Plant Extracts / Q000494:pharmacology*; D028321:Plant Preparations / Q000494:pharmacology*; D031364:Scutellaria baicalensis / Q000737:chemistry*; D019098:Telomerase / Q000378:metabolism
chemical_list: D004967:Estrogens; D005231:Fatty Acids, Unsaturated; D016328:NF-kappa B; D010936:Plant Extracts; D028321:Plant Preparations; C499814:Scutellaria baicalensis extract; D019098:Telomerase